new to using thhn/emt

ststewartdvmMarch 31, 2011

Thanks for any help. I have been reading the NEC and have passed my county's homeowner's exam to get my permit. I am going to be adding a sub and circuits to my attached garage. I need to do surface mount for the new circuits b/c of the time and trouble to redo the drywall already up. I therefore will be using EMT and THHN for my job. I understand that the conduit is attached to a set screw connector and the fitting goes into the junction box/panel and is locknutted to secure the conduit/connector into place. I will be running a separate grounding conductor. Is there some sort of bushing/clamp that has to be used inside the set screw connector for protection of the wires as it comes out of the connector? Also does the THHN have to be clamped in any way like Romex has to be clamped as it comes into a box?

No one seems to say anything about a bushing, so I think it's not needed, but I don't want to miss something so obvious that no one talks about it either.

Thank you very much,


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Ron Natalie

The code requires bushings for #4 wire and larger. You may consider it for smaller wires. There are actually connectors that have the bushing integral.

There's no need for most wiring to be internally clamped at the box. The clamp on the NM is to keep it from exiting the box because there's nothing else potentially holding it.

    Bookmark   April 1, 2011 at 9:09AM
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If I could offer a bit of unsolicited advice, bending EMT is as much art as anything else and the best results are obtained through practice, lots of practice. When you buy your supplies, a few extra sticks of pipe might save you a second trip to the hardware store.

If you mount your pipe flush to the wall, you'll need to bend an offset at the end of the run where it enters the box. They do sell clamps that hold the pipe the correct distance off the wall as to eliminate the need to bend the offset.

Just a thought.

    Bookmark   April 3, 2011 at 9:45AM
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Make sure you ream the inside of the emt after you cut it so as not to scar the insulation on the thhn.

    Bookmark   April 3, 2011 at 4:38PM
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Thank you for all the replies.

    Bookmark   April 23, 2011 at 11:21AM
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